CB1 :

Where did your original feed trained LMB come from (the brood fish source)? Metabolic rate in general, as measured by normal heart rate, is a limiting factor on life span. In general the smaller the animal the higher the heart rate and the shorter the life span. For example mice- 2-3 yrs, dogs- 7-15 yrs. , people- 75 yrs. Not sure about fish but I know smaller fish species seem ,from the data to have shorter life spans ie. minnows vs BG vs LMB vs sturgeon. Within a single population (species) I don't know ; as smaller dogs generally have longer life spans and Florida LMB have longer life spans than Northern LMB in the same intermediate conditions ( Miss, Tex. , Calif. not NY vs Fla. or Fla. vs Ill.) In individual situations like LMB from one brood stock source vs another similar source I don't know . Unlike a candle here genetics and conditions (stress etc) have a big part. to do with the answer. As a general matter though the more you run the engine at high end speed the sooner (in time not out put) the engine wears out. Good questions and many unanswered ones .